Plastic cards such as pre-paid telephone cards and similar prepaid debit cards are vended from vending machines away from service facilities for the vending machines. It is therefore essential that the plastic cards be immediately available from the vending machine without hindrance or obstruction caused by static electricity building on the plastic material face of the card. Building of the static electricity upon the face of the card can result in failure of the vending machine to dispense the cards one by one, thus requiring service intervention of the vending machine to continue operation of the machine.
Plastic cards vended by a vending machine slide down a metal chute from a source sleeve to the discharge outlet. The slide of the card down the metal chute can build up a static charge on the plastic card to stop the card from sliding down the chute and cause the cards to jam-up in the chute every two or three cards.
The generation of static electricity upon non-conductive surfaces of material such as plastics and paper is well-known. The build-up can cause articles made of such materials to adhere together on their surfaces or to other materials. A cause of such generation of static electricity can be friction encountered by the card sliding down the card delivery chute of the vending machine. Numerous methods and devices can be applied to dissipate the static electric charge. However, application of an anti-friction substance to prevent or reduce friction and thus prevent or reduce buildup of static electricity upon the plastic card as the card is processed by the vending machine can negate the need to provide conventional devices to dissipate the static electrical charges that develop upon the plastic cards.
The application of an anti-friction substance to prevent static electricity buildup requires that each individual card receive an application of an anti-friction substance in sufficient measure to prevent static electricity buildup by and on each individual card. Each individual card is therefore required to be treated separately to receive an individual application of an anti-friction substance. Treatment of individual cards upon a production line for such cards for use in vending machines requires that the cards be treated in a continuous operation and that each card receive a controlled amount of an anti-friction substance upon the surface of each card.
The problems inherent in placing a controlled amount of an anti-friction substance upon the surface of each individual card are problems of control and measurement of the anti-friction material as the anti-friction material is applied to the surfaces of the plastic cards. The anti-friction material is typically applied as a powder.
The anti-friction material can be subject to problems of application to the cards because of the ambient environment of temperature and humidity. The combination of temperature and humidity conditions can cause this anti-friction material as a powder to cake and from a lumpy condition versus a powdery condition which can be easily applied to the surfaces of the plastic cards. The problem of control to obtain a coating of anti-friction material upon each card surface therefore becomes significant. The combination of temperature and humidity can effect the adherence of the powder to the surfaces of the plastic card, causing the card to not have enough anti-friction material to be less than a to-be-required amount or to be greater than a to-be-required amount. If the amount is less than a required level, the anti-friction condition, as measured by a test measure, is inadequate. If the amount is greater than a required level, anti-friction condition of the plastic card is excessive as measured by a test measure and the card needs to be reprocessed.
De-ionized air, applied as a blast of air, instead of a powder, can be used to control generation of static electricity upon plastic cards but the effect in controlling the generation of static electricity is not as permanent as use of a powder.
The process and apparatus for preparation of a no-jam vending machine plastic card accordingly comprises a dusting machine which applies a controlled amount of powder to a series of plastic cards which pass through the dusting machine and a test unit which measures the amount of anti-friction powder applied to each card during passage through the dusting machine. The dusting machine comprises two chambers that are separate and closed to each other. In a first chamber, the anti-friction material is applied to each card, one-by-one. In the second chamber, excess anti-friction material is removed to provide a suitable vending machine plastic card. The product of the second chamber is tested in a test unit to verify that the no-jam vending machine plastic card has the no-jam characteristics required for use in a vending machine.
In the prior art, a number of patents teach devices and methods of application for coating powder upon objects and dispensing objects wherein problems of application and utility in vending machines and of coating powder are disclosed.
U.S. Pat. No. 6,510,788 to Norheim discloses a device for application of coating powder in a screen or offset printing process wherein an adhesive powder is applied to a printed material that can be heat transferred to a garment. In Christmas cards, a printed area is often coated with different powders, the excess powder being removed. The device utilizes a conveyor with an air permeable conveyor surface for conveying a base sheet in a direction of travel, the base sheet being coated with a coating powder upstream of the conveyor. The powder-applying device includes a vibrating hopper. An air jet used as an air-knife removes excess powder from the base sheet. A suction device beneath the conveyor forces the excess coating powder to pass through the conveyor surface. U.S. Pat. No. 6,497,371 to Kayanakis teaches use of silvery powder as a protective coating as a component of an electronic module comprising an integrated circuit and an antenna, the antenna formed of the silvery powder. U.S. Pat. No. 6,425,344 to Strahm discloses a device for coating a web-like sheet formation wherein a thermoplastic powder is scattered over a surface, the powder is thermally treated, and an air jet swirls up the powder and a suction means removes the swirled up powder. U.S. Pat. No. 6,267,370 to Ito, et al., discloses a mechanical card dispensing device for an automatic card vending machine whereby the device has a mechanism for preventing double feeding of cards so as to dispense the cards one-by-one. The double feed preventing mechanism utilizes rollers which feed the dispensing cards from a card feed route to the double feed preventing mechanism. U.S. Pat. No. 6,231,042 to Ito, et al., discloses a card dispensing device which has a mechanism for forcibly modifying the altitude of an inclining slide for a card dispensing device of an automatic card vending machine. The altitude of the slide is modified from a horizontal level in which a vending machine card is being pushed forward to an inclined altitude to dispense the card and then the slide is forcibly returned to its initial horizontal altitude. U.S. Pat. No. 6,199,757, to Kubert, discloses a method of removing a vending machine card from a stack of vending machine cards by friction between the card and stripper belts through a pre-shingler and through a series of stripper fingers which guide the card into a card feed discharge assembly. U.S. Pat. No. 5,654,050, to Whalen-Shaw, discloses a playing card of paper which is laminated with plastic films on both sides. The films are mechanically embossed with embossments that provide a static slip in the range of from about 7° to 15°. The amount of static slip avoids having one card stick with respect to another. Static slip is taught as being measured by placing a pair of cards on an adjustable incline and determining the angle at which one card slips with respect to the other, the static slip being measured in degrees. The embossments are spherical indentations made in the surface of the films in the nip of a roll machine. Each indentation had a depth of about 20 microns. The frequency of the indentations was 344 per square centimeter. The cards were embossed after lamination with plastic films. Samples of the embossed, laminated cards were measured also for gloss. Reported static slips of the cards were in terms of average slip degrees and statistical deviation. A slip in the range of about 7° to 15° is considered acceptable. U.S. Pat. No. 4,873,937 to Binder, et al., discloses a method and apparatus for spraying a particulate powder material into a continuous roving or tow formed of individual strands. The apparatus comprises a hollow spraying chamber having inlet and outlet guides for receiving the tow moving axially therethrough. A stream of air-entrained particulate powder is injected into the hollow spraying chamber, at an angle relative to the direction of movement of the tow. The air velocity is such that the individual strands of the tow are separated from one another and the particulate powder material is lodged between the exterior surfaces of adjacent strands throughout substantially the entire thickness of the tow.
Although aspects and elements of the current invention are taught in the prior art, i.e., the use of a conveyor in conjunction with a powder applying device including a vibrating hopper, an air-knife to remove excess powder and a suction device to remove excess powder; the use of a powder as a protective coating; the use of an air jet to swirl up an applied powder and a suction means to remove the applied powder; a mechanical card dispensing device wherein the device has a mechanism for preventing double feeding of cards versus a one-by-one feeding from a card dispensing machine; the method of removing a vending machine card from a stack of vending machine cards by use of friction belts and stripper fingers into a card discharge assembly; and a card with embossments to provide static slip, the static slip being measured by slip of cards upon an adjustable incline, the angle of slip in degrees indicating slip; the instant invented process and apparatus for preparation for a no-jam vending machine plastic card has not been disclosed in the prior art. Additional elements of the invented process include a test procedure of a multiple number of random samples of up to 100% testing of the vending machine plastic cards to insure no card will fail ejection from the vending machine, the process and apparatus providing cards that are treated before placement in a vending machine to provide the necessary slip factor without the need of additional devices within the vending machine. The treated cards can be used in conventionally available vending machines of conventional design. The plastic cards after the treatment process are suitable for use in vending machines under conditions of increased humidity and temperature found in off shore locations such as ocean-going vessels operating all over the world and in locations of high heat and humidity conditions.